keystone species
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2022 ◽  
Author(s):  
Justin Kestler

Mammalian predators are keystone species in any ecosystem. But many are elusive by nature and have territories that cover large areas of land, which makes them challenging to monitor. When tracks and signs prove difficult to interpret or are non-existent, hair samples recovered from the field offer a fantastic resource – one that is often overlooked. The Hair Scale Identification Guide to Terrestrial Mammalian Carnivores of Canada provides a fully illustrated, up-to-date hair scale reference for all 25 of the terrestrial carnivorous mammals of Canada. From the tiny least weasel (Mustela nivalis) to the giant polar bear (Ursus maritimus), unique traits – as well as tricky similarities – can clearly be observed through hair scale patterns magnified at the medial portion of the hair impression. These scale patterns aid in species identification when hair is the only possible evidence available. This guide also outlines hair impression techniques for samples found in the field, assisting ecologists and technicians with wildlife monitoring studies on predatory mammals where additional identification is required. Including range maps and key identification characteristics for all species represented, as well as superb images of hair scale impressions at two magnification levels, this book is a comprehensive tool for animal hair ID.


PeerJ ◽  
2022 ◽  
Vol 9 ◽  
pp. e12705
Author(s):  
Guangjie Fang ◽  
Haolin Yu ◽  
Huaxiang Sheng ◽  
Chuanxi Chen ◽  
Yanli Tang ◽  
...  

Marine bacteria in the seawater and seafloor are essential parts of Earth’s biodiversity, as they are critical participants of the global energy flow and the material cycles. However, their spatial-temporal variations and potential interactions among varied biotopes in artificial habitat are poorly understood. In this study, we profiled the variations of bacterial communities among seasons and areas in the water and sediment of artificial reefs using 16S rRNA gene sequencing, and analyzed the potential interaction patterns among microorganisms. Distinct bacterial community structures in the two biotopes were exhibited. The Shannon diversity and the richness of phyla in the sediment were higher, while the differences among the four seasons were more evident in the water samples. The seasonal variations of bacterial communities in the water were more distinct, while significant variations among four areas were only observed in the sediment. Correlation analysis revealed that nitrite and mud content were the most important factors influencing the abundant OTUs in the water and sediment, respectively. Potential interactions and keystone species were identified based on the three co-occurrence networks. Results showed that the correlations among bacterial communities in the sediment were lower than in the water. Besides, the abundance of the top five abundant species and five keystone species had different changing patterns among four seasons and four areas. These results enriched our understanding of the microbial structures, dynamics, and interactions of microbial communities in artificial habitats, which could provide new insights into planning, constructing and managing these special habitats in the future.


2021 ◽  
Vol 90 ◽  
Author(s):  
Fengke Lin ◽  
Binsheng Luo ◽  
Zhuo Cheng ◽  
Ping Li ◽  
Chunlin Long

Abstract The genus Garcinia L. (Clusiaceae) is gaining increasing scientific attention worldwide owing to its ethnobotanical and pharmacological significance. In China, even though Garcinia plants have long been used for food, ethnomedicine, building materials, and other purposes, a comprehensive ethnobotanical study of the genus is notably limited. In the current study, the ethnobotanical importance of Garcinia plants has been extensively investigated through field surveys and literature reviews. Our studies revealed that Garcinia plants have been used in folk medicine since ancient times in China, including the Northern Song Dynasty, 960–1127 AD. Through their extensive interactions with genus, the Chinese people have gained various traditional knowledge, which is reflected in the following six aspects: food, traditional medicines, ornamental trees, construction and technology, cultural and spiritual significance, and miscellaneous uses. In particular, the four species: Garcinia hanburyi , G. paucinervis , G. xanthochymus , and G. oblongifolia , have cultural or spiritual values, among which G. paucinervis could be considered a cultural keystone species in the local communities, considering its crucial contribution to people’s cultures, spirits, and community identity. However, in general, some concerns originating from swift socio-economic changes have also been identified in the knowledge and Garcinia species. Strategies are needed to conserve traditional botanical knowledge, as well as plants.


2021 ◽  
Vol 8 ◽  
Author(s):  
Kyle W. Fouke ◽  
Jeffrey M. Trop ◽  
Mayandi Sivaguru

Next-generation high resolution brightfield microscopy, x-radiography, and microcomputed tomography (microCT) analyses indicate that coral skeleton high density band (HDB) and low density band (LDB) stratigraphic sequences record dynamic changes in coral growth history. HDB-LDB sequences were studied within three small heads of Orbicella annularis, an ecological keystone species in the Caribbean Sea, collected from the leeward fringing reefs on Curaçao. Results indicate that HDB layers are formed by the thickening of exothecal and endothecal dissepiments, costae, and theca located at the margin and external to individual skeletal cups (corallites). Conversely, septa and columellas located inside individual corallites do not change in thickness. HDB-LDB stratigraphic sequences were laterally traced from the center to the margins of individual coral heads, demonstrating that shifts took place in the trajectory of coral skeleton growth. Normal HDB layers in the center of individual coral heads are formed at the same time (age-equivalent) as surfaces of erosion and no skeleton growth (hiatuses) on the margins of the heads. These hiatus surfaces within HDB-LDB stratal geometries indicate that multiple marine ecological and environmental processes affect the orientation, size, shape, and geometry of coral skeletons during coral growth history. The presence of these hiatus surfaces in other large coral heads would strongly impact sclerochronology and the interpretation of multiple environmental factors including sea surface temperature (SST).


2021 ◽  
Vol 118 (52) ◽  
pp. e2107977118
Author(s):  
Alistair J. Monteath ◽  
Benjamin V. Gaglioti ◽  
Mary E. Edwards ◽  
Duane Froese

The collapse of the steppe-tundra biome (mammoth steppe) at the end of the Pleistocene is used as an important example of top-down ecosystem cascades, where human hunting of keystone species led to profound changes in vegetation across high latitudes in the Northern Hemisphere. Alternatively, it is argued that this biome transformation occurred through a bottom-up process, where climate-driven expansion of shrub tundra (Betula, Salix spp.) replaced the steppe-tundra vegetation that grazing megafauna taxa relied on. In eastern Beringia, these differing hypotheses remain largely untested, in part because the precise timing and spatial pattern of Late Pleistocene shrub expansion remains poorly resolved. This uncertainty is caused by chronological ambiguity in many lake sediment records, which typically rely on radiocarbon (14C) dates from bulk sediment or aquatic macrofossils—materials that are known to overestimate the age of sediment layers. Here, we reexamine Late Pleistocene pollen records for which 14C dating of terrestrial macrofossils is available and augment these data with 14C dates from arctic ground-squirrel middens and plant macrofossils. Comparing these paleovegetation data with a database of published 14C dates from megafauna remains, we find the postglacial expansion of shrub tundra preceded the regional extinctions of horse (Equus spp.) and mammoth (Mammuthus primigenius) and began during a period when the frequency of 14C dates indicates large grazers were abundant. These results are not consistent with a model of top-down ecosystem cascades and support the hypothesis that climate-driven habitat loss preceded and contributed to turnover in mammal communities.


2021 ◽  
Vol 9 ◽  
Author(s):  
Guy Woodward ◽  
Olivia Morris ◽  
José Barquín ◽  
Andrea Belgrano ◽  
Colin Bull ◽  
...  

Populations of Atlantic salmon are crashing across most of its natural range: understanding the underlying causes and predicting these collapses in time to intervene effectively are urgent ecological and socioeconomic priorities. Current management techniques rely on phenomenological analyses of demographic population time-series and thus lack a mechanistic understanding of how and why populations may be declining. New multidisciplinary approaches are thus needed to capitalize on the long-term, large-scale population data that are currently scattered across various repositories in multiple countries, as well as marshaling additional data to understand the constraints on the life cycle and how salmon operate within the wider food web. Here, we explore how we might combine data and theory to develop the mechanistic models that we need to predict and manage responses to future change. Although we focus on Atlantic salmon—given the huge data resources that already exist for this species—the general principles developed here could be applied and extended to many other species and ecosystems.


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